Burnishing machine

ABSTRACT

An apparatus for burnishing a tube includes a housing having an inner surface defining a passage. A shaft provided in the passage is rotatable therein. An eccentric cam extends from the shaft and is rotatable therewith. The tube is configured for positioning within the passage and around the cam such that rotation of the cam simultaneously removes burrs from inner and outer surfaces of the tube.

RELATED APPLICATION

This applications claims priority to U.S. Provisional Application Ser. No. 63/031,672, filed May 29, 2020, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to tube processing and, more specifically, relates to an apparatus and method for de-burring tubes.

BACKGROUND

As a typical industry standard, de-burring of cut metal tubing and piping is traditionally performed with one or more existing methods, such as abrasive rotating, oscillating, grinding or wire-wheel type machines. These machines can be powered by electric, hydraulic or pneumatic motors and remove burrs left on the tube from a previous cutting process. These methods, however, have high costs due to the frequent replacement of the consumable grinding/wire wheels used. The excess costs stem not only from the replacement but also in change over and set-up times.

SUMMARY

In one example, an apparatus for burnishing a tube includes a housing having an inner surface defining a passage. A shaft provided in the passage is rotatable therein. An eccentric cam extends from the shaft and is rotatable therewith. The tube is configured for positioning within the passage and around the cam such that rotation of the cam simultaneously removes burrs from inner and outer surfaces of the tube.

In another example, an apparatus for burnishing a tube includes a housing having an inner surface defining a passage and a hard stop within the passage for locating the tube within the housing. A shaft provided in the passage. An eccentric cam extends from the shaft and includes a lobe having an elliptical rotational path about an axis of the shaft when the shaft and cam rotate together within the passage. The tube is configured for positioning within the passage and around the cam such that rotation of the cam simultaneously removes burrs from inner and outer surfaces of the tube.

In another example, a method for burnishing a tube includes providing a housing having an inner surface defining a passage. A shaft having an eccentric cam extending therefrom is provided within the passage such that rotation of the shaft about an axis results in an elliptical rotational path of the cam about the axis. A tube is inserted between the rotating cam and the inner surface to simultaneously remove burrs from inner and outer surfaces of the tube.

Other objects and advantages and a fuller understanding of the invention will be had from the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an example burnishing apparatus.

FIGS. 2-3 are schematic illustrations of the interior of the burnishing apparatus of FIG. 1.

FIG. 4 is a schematic illustration of an eccentric cam of the burnishing apparatus of FIG. 1.

FIG. 5 is a schematic illustration of a tube for use in the burnishing apparatus.

FIG. 6 is a schematic illustration of the burnishing apparatus of FIG. 1 connected to an outer frame.

DETAILED DESCRIPTION

The present invention relates generally to tube processing and, more specifically, relates to an apparatus and method for de-burring tubes. One example apparatus 20 is illustrated in FIGS. 1-4. Referring to FIGS. 1-2, the apparatus 20 includes a cover 22 provided on a base or frame 24. The cover 22 extends longitudinally from a first end 30 to a second end 32 and cooperates with the base 24 to define an interior space 34. An opening 36 is formed in the second end 32 and extends to the interior space 34. A motor 40 is provided at the first end 30 of the cover 22 and rotates about an axis 42.

A housing 50 is provided in the interior space 34 and connected to the base 24. In one example, compression springs 52 mount the housing 50 to the base 24 and allow the housing to move or float vertically (as shown) relative to the base in the manner indicated at A₁. The housing 50 extends from a first end 53 to a second end 55. An inner surface 56 defines a passage 54 extending between the ends 53, 55 through the entire length of the housing 50 along a path aligned with the axis 42 of the motor 40. The inner surface 56 can be chamfered at the second end 55 leading into the passage 54.

One or more bearings 60 are secured to the base 24 between the motor 40 and the housing 50, i.e., adjacent the first end 53 of the housing 50. The bearings 60 are fixed in place and therefore do not move vertically relative to the base 24.

Referring to FIG. 3, a second housing 70 is provided adjacent the second end 55 of the housing 50 and is spaced therefrom by a gap 72. In one example, compression springs 82 mount the second housing 70 to the base 24 and allow the second housing to move or float vertically (as shown) relative to the base in the manner indicated at A₂. The second housing 70 acts as tube guide, as will be discussed. The second housing 70 extends from a first end 74 to a second end 76. A passage 80 extends between the ends 74, 76 through the entire length of the second housing 70. The passage 80 is aligned with the axis 42 and the passage 54 in the housing 50. A proximity sensor 84 is provided between the housings 50, 70 and has a field of view extending into the gap 72.

A subassembly 88 (FIG. 4) includes a shaft 90 and a cam 98 secured thereto. The shaft 90 extends longitudinally along an axis 92 from a first end 94 to a second end 96. The cam 98 is secured to the shaft 90 and rotates with the shaft about the axis 92. The cam 98 includes a body 100 and a lobe 102 secured thereto or integrally formed therewith. In any case, the lobe 302 extends from the body 100.

The body 100 is concentric with the shaft 90 and spaced from the first end 94. The lobe 102 is provided on the second end 96 of the shaft 90 and forms an eccentric portion of the cam 98. The shaft 90 can be formed from a durable material, e.g., cold rolled steel, and can be coated with a high temperature coating, e.g., TiAlCN, using a duplex-variantic process. The lobe 102 can be formed from, for instance, M2 tool steel. Other materials and coatings are contemplated.

The first end 94 of the shaft 90 is secured to the motor 40 such that the subassembly 88 is rotatable with the motor 40 about the axes 42, 92 as indicated at R in FIG. 2.

The body 100 of the cam 98 is received in the bearings 60 and rotatable therewith. The second end 96 of the shaft 92 and the lobe 102 are provided in the passage 54 of the housing 50. When this occurs, the axes 42, 92 are coextensive. The body 100 is centered on the axes 42, 92 and the lobe 102 extends radially outward from the axes.

A tube 110 for use in the apparatus 20 is shown in FIG. 5. The tube 110 extends longitudinally along a centerline 112 from a first end 114 to a second end 116. The first end 114 and/or second end 116 can be cut square (perpendicular to the centerline 112) or tapered relative thereto, e.g., at or about 45° (not shown). In one example, the tube 110 can have an outer diameter of about 2″. An inner surface 118 defines a passage 120 extending the entire length of the tube 110 along the centerline 112. The tube 110 also includes an outer surface 122. Following a cutting, forming, etc., operation performed on the tube 110, one or both of the inner surface 118 and outer surface 122 can include metal burrs, indicated at B at one or both ends 114, 116. It is desirable to remove these burrs B prior to downstream processing of the tube 110.

In operation, the first end 114 of the tube 110 is inserted by the operator through the passage 80 in the second housing 70 and into the passage 54 in the housing 50. When this occurs, the first end 114 of the tube 110 becomes positioned radially between the inner surface 56 of the housing 50 and the lobe 102. In this manner, the second housing 70 acts as a guide for helping position the tube 110 in the first housing 50. The first housing 50 can include an axial surface (illustrated in phantom at 35) positioned along the passage 54 to act as a hard stop for insertion of the tube 110 into the passage. In other words, the hard stop 75 acts to accurately/automatically position the first end 114 of the tube 110 over the lobe 102 and within the passage 54. The proximity sensor 84 cooperates with a controller 87 to alert the operator when the tube 110 is inserted into the housings 50, 70.

The motor 40 is then activated to rotate the subassembly 88 about the axes 42, 92. This causes the cam 98 and, more specifically, the lobe 102 to eccentrically rotate about the axis 92 within the passage 92 along an elliptical path. In one example, the shaft 50 is rotated between about 1000 and 2000 RPM. That said, the elliptical pattern/path of the lobe 102 burnishes the inner surface 118 of the tube 110, thereby removing any burrs B thereon.

At the same time, the outer surface 122 of the tube 110 is burnished against the inner surface 56 of the housing 50. More specifically, the elliptical motion of the lobe 102 causes the tube 110 to move radially relative to the axis 92 of the rotating shaft 90 and thereby move into and out of contact with the inner surface 56. By forming the inner surface 56 from a harder material than the tube 110, abrasion between the tube and inner surface removes any burrs B on the outer surface 122 of the tube 110. The springs 52, 82 allow the housings 50, 70 to move in the manners A₁, A₂ sufficient to burnish the inner and outer surfaces 118, 122 of the tube 110 while preventing unnecessary stress accumulation in the apparatus 20 or tube.

One or more pressurized fluid sources, e.g., compressed air jets (not shown), can be fluidly connected to the passage 54 of the housing 50 to provide forced air to the passage during burnishing. The air jet(s) can, for example, be longitudinally aligned with the passage 54 and/or integrated into the wall of the housing 50 to direct compressed air into the passage during operation of the apparatus 20. The compressed air can serve the dual purpose of cleaning and cooling the rotating/abrading components.

Once any burrs B are removed from the first end 114 of the tube 110, the tube is removed from the housings 50, 70 and the process is repeated with the second end 116 of the tube to remove any burrs thereon.

The apparatus 20 is illustrated in FIGS. 1-2 as being provided in/on a frame 24 positioned or mounted on a flat, stable surface, such as a warehouse or factory floor (not shown). Rotation of the motor 40 during removal of the burrs B can induce vibrations in one or more components of the apparatus 20, which are then transferred to the frame 24 secured thereto. That said, it may be desirable to dampen these vibrations in an effort to reduce noise and/or wear on the apparatus 20 and/or frame 24.

With this in mind, FIG. 6 is an example system for helping to dampen vibrations induced in the apparatus 20. In this example, the frame 24 and apparatus 20—including the motor 40 and housings 50, 70 secured thereto—are positioned within and connected to an outer frame 150. The outer frame 150 include a base 152 and a back or rear member 154 extending upwards therefrom. A pair of arms 156 extend away from the rear member 154. A pair of arms 158 extend upwards and away from the base 152. The base 152, rear member 154, and arms 156, 158 cooperate to define an interior space 160 for receiving the frame 24.

One or more projections 160, 162, 164 extend from the rear member 154 and arms 158, respectively. An opening extends through each projection 160, 162, 164. A corresponding series of the projections 25, 27 extend from the rear and front, respectively, of the frame 24. An opening extends through each projection 25, 27. Alternatively, the openings can extend directly through the frames 24, 150 with the projections being omitted (not shown). More or fewer projections provided along any of the sides of the frame 24 and/or along the outer frame 150 are contemplated.

In any case, suspension member 170 are secured to, e.g., extend through the openings of, associated pairs of the projections 25, 160, associated pairs of the projections 27, 162, and associated pairs of the projections 27, 164. The suspension members 170 can be springs, cables, or the like capable of securely fastening the frame 24 to the outer frame 150. In one example, each suspension member 170 can be a tunable wire/cable that is adjustable with a centrally mounted turnbuckle. The suspension members 170 therefore alleviate any direct connection by fastener, etc. between the frame 24 and the outer frame 150.

Regardless of the particular construction of the suspension members 170 and the connection thereof to the frames 24, 150, the suspension members are configured to acts as a tuned mass damper to cancel or mitigate sound, harmonics, and/or excessive vibration in the apparatus 20 that would otherwise be transmitted to the frame 24. To this end, the suspension members 170 allow the vibrating apparatus 20 to move in one or more directions (indicated generally at A₃) relative to the outer frame 150. Dampening the vibration helps to cancel or reduce stresses in the frame 24 and any components of the apparatus 20 connected thereto, which helps to prolong the lifespan of the apparatus.

The apparatus shown and described herein advantageously uses no discs, belts, wire wheels or consumable abrasive media to perform the burnishing process. Moreover, no chips, debris, swarf or dust is created. The apparatus can cycle at, for example, 1.9 seconds per tube with the tube being self-supported. The apparatus can be sized to accommodate a tube having any inside or outside diameter and/or having one or more square or tapered ends.

What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. 

What is claimed is:
 1. An apparatus for burnishing a tube, comprising: a housing having an inner surface defining a passage; and a shaft provided in the passage and being rotatable therein, an eccentric cam extending from the shaft and being rotatable therewith, the tube being configured for positioning within the passage and around the cam such that rotation of the cam simultaneously removes burrs from inner and outer surfaces of the tube.
 2. The apparatus recited in claim 1, wherein the eccentric cam includes a lobe having an elliptical rotational path about an axis of the shaft.
 3. The apparatus recited in claim 1, further comprising at least one spring for connecting the housing to a base and allowing for vertical movement of the housing relative to the base during burnishing of the tube.
 4. The apparatus recited in claim 1, further comprising a tube guide aligned with the housing for guiding the tube into the passage.
 5. The apparatus recited in claim 4, further comprising a proximity sensor positioned between the housing and the tube guide for sensing the presence of a tube to be burnished.
 6. The apparatus recited in claim 4, further comprising at least one spring for connecting the tube guide to a base and allowing for vertical movement of the tube guide relative to the base during burnishing of the tube.
 7. The apparatus recited in claim 1, further comprising at least one fluid nozzle for supplying pressurized fluid to the passage of the housing.
 8. The apparatus recited in claim 1, further comprising a motor for rotating the shaft at a speed of at least 1500 RPM.
 9. The apparatus recited in claim 1, wherein the housing includes a hard stop within the passage for locating the tube relative to the cam within the housing.
 10. A system for burnishing a tube comprising: the apparatus of claim 1; an outer frame defining an interior space for receiving the apparatus; and suspension members connecting the apparatus to the outer frame for damping vibrations therebetween.
 11. An apparatus for burnishing a tube, comprising: a housing having an inner surface defining a passage and a hard stop within the passage for locating the tube within the housing; and a shaft provided in the passage, an eccentric cam extending from the shaft and including a lobe having an elliptical rotational path about an axis of the shaft when the shaft and cam rotate together within the passage, wherein the tube is configured for positioning within the passage and around the cam such that rotation of the cam simultaneously removes burrs from inner and outer surfaces of the tube.
 12. The apparatus recited in claim 11, further comprising at least one spring for connecting the housing to a base and allowing for vertical movement of the housing relative to the base during burnishing of the tube.
 13. The apparatus recited in claim 11, further comprising a tube guide aligned with the housing for guiding the tube into the passage.
 14. The apparatus recited in claim 13, further comprising a proximity sensor positioned between the housing and the tube guide for sensing the presence of a tube to be burnished.
 15. The apparatus recited in claim 13, further comprising at least one spring for connecting the tube guide to a base and allowing for vertical movement of the tube guide relative to the base during burnishing of the tube.
 16. The apparatus recited in claim 11, further comprising at least one fluid nozzle for supplying pressurized fluid to the passage of the housing.
 17. The apparatus recited in claim 11, further comprising a motor for rotating the shaft at a speed of at least 1500 RPM.
 18. The apparatus recited in claim 11, wherein the housing includes a hard stop within the passage for locating the tube relative to the cam within the housing.
 19. A system for burnishing a tube comprising: the apparatus of claim 11; an outer frame defining an interior space for receiving the apparatus; and suspension members connecting the apparatus to the outer frame for damping vibrations therebetween.
 20. A method for burnishing a tube, comprising the steps of: providing a housing having an inner surface defining a passage; providing a shaft having an eccentric cam extending therefrom within the passage such that rotation of the shaft about an axis results in an elliptical rotational path of the cam about the axis; and inserting a tube having burrs between the rotating cam and the inner surface to simultaneously remove burrs from inner and outer surfaces of the tube. 